why doesn't my hair stay curly?

After I wash my hair I have beautiful curls, but when it dries a lot of that goes away. especially if I put it in a ponytail. it just all straightens out by itself! I haven't had a perm since I was about 8/9 so I just don't understand why I can't maintain them.

whenever I just let my hair air dry you just can't see my curl pattern anymore. I think the ponytail does pull the curl out but I don't do that too often. I use Shea Moisture conditioner, Dark&Lovely Naturale conditioner, & Eco Styler gel.